1. Field of the Disclosure
This disclosure is directed to transformers.
2. Related Art
In many applications, for example, shipboard and aircraft applications, a high voltage direct current (DC) power is used to power motor controllers. Typically, a three phase alternating current (AC) voltage of 230 Volts (root mean square (rms)) is generated in a ship or an aircraft and the generated AC voltage is applied to an auto transformer rectifier unit (ATRU). The ATRU generates a DC voltage of +/− 270 Volts. The DC voltage from the ATRU is used to power motor controllers.
The voltage output of the motor controllers is limited by the rectified DC voltage of the ATRU. It is desirable to increase the voltage output of the motor controllers.
In order to increase the voltage output of the motor controllers, various approaches have been tied. One approach is to generate a higher input AC voltage from the generator. This approach has shortcomings because by increasing the generator output AC voltage, the insulation level of the ship or aircraft has to be increased. Furthermore, increased input AC voltage leads to additional challenges like corona, high voltage spikes and component breakdown.
Another approach has been to add a step-up (or step up) autotransformer before the motor controller to get a higher rectified, output DC voltage or after the motor controller to get a higher output AC voltage. Adding an additional step-up transformer before or after the motor controller adds additional heavy components to the overall power generation system. This increases overall weight of the system and is undesirable in environments that may be sensitive to weight, for example, ships and aircrafts.
Continuous efforts are being made to deal with the foregoing issues.